26 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Hypalocrinus naresianus 



Isocrinus (genotype Isocrinus pendulus von Meyer, 1837); differs from Hypa- 

 locrinus in having one interpolated series, followed by one or more extraneous series; 

 basals narrow, forming, in dorsal view, a rounded stellate figure; infrabasals large 

 and prominent (determined from an examination of 15 specimens of /. decorus, 

 including a very small 10-armed individual with arms 25 mm. long; material of 

 other species was not available). 



Two subgenera are recognized, Cenocrinus, in which the first two postradial 

 ossicles are united by syzygy, the lower pinnules are serrate, and the reentrant 

 angles of the stellate figure formed by the basals shallow, and Isocrinus, in which 

 the first two postradial ossicles are united by synarthry, the lower pinnules are 

 smooth, and the reentrant angles of the stellate figure formed by the basals deep. 



The species of Isocrinus are : 



Isocrinus (Cenocrinus) asteria. Isocrinus (Isocrinus) blakei. 



Isocrinus (Isocrinus) decorus. 



Endoxocrinus (genotype Encrinus parrae Gervais, 1835 [ = Pentacrinus mulleri 

 Orsted, 1856]): Z[ and Z 2 are the first and second ossicles of the free undivided arm 

 and are separated from the radials by two or more interpolated series; infrabasals 

 always (?) absent (infrabasals were absent in all the specimens dissected, including 

 one with arms only 25 mm. long). The included species are: 



Endoxocrinus alternicirrus. Endoxocrinus sibogae. 



Endoxocrinus parrae. Endoxocrinus wyville-thomsoni. 



Pentacrinus maclearanus Wyville Thomson is stated to be merely a rather 

 strongly marked variety of Endoxocrinus parrae. 



Two new names are used ; Metacrinus superbus borealis is said to differ from the 

 typical form mainly in having the division series and arm bases smooth instead of 

 very rough ; Metacrinus superbus tuberculatus is said to have the division series with 

 strong tubercles, but otherwise resembling the preceding. Although not so stated, 

 both these supposed varieties are from the Eastern Sea off Kagoshima. 



Just over a year after I described the genus Ptilocrinus and the type species 

 Pt. pinnatus, Dr. F. A. Bather described a second species of the genus, Pt. antarcticus, 

 which had been dredged by the Belgian Antarctic Expedition in 480 meters in the 

 region south of Cape Horn. In a review of this paper published on July 31 the dis- 

 tribution of the crinoids as a whole was discussed. 



Three faunal regions were recognized, as follows: 



(1) The Indo-Pacific-Japanese, characterized by the families Zygometridae and 

 Himerometridae, the genera Comatula, Phanogenia, and most of the species of Co- 

 master, in the Comasteridae, the genera Ptilometra, Asterometra, Calometra, and one 

 of the two species of Tropiometra (the second species, T. carinata, appears to have 

 recently extended its range into the Atlantic) of the Tropiomctridae, and the genera 

 Perometra, Nanometra, Compsometra, Thysanometra, and Iridometra of the Ante- 

 donidae; among the stalked crinoids Metacrinus, Carpenter ocrinus, Hypalocrinus, 

 and Phrynocrinus are only known from this region. 



